92' 70hp Force, after stator and fuel pump replacement, still cuts out at high speed

[markjpro]

70 hp Force that cuts out at high speed, usually, replaced stator, trigger,(CD)I fuel pump and diaphragm, plugs, primer bulb, pulled vent off fitting, flushed tank, swapped tanks, checked carb and needle seat, checked choke solenoid, terminals, it charges and took regulator out of loop running with yellow stator wires off, no change... always fresh water, checked all power pack nuts and coil grounds, bulb is always very firm. Runs better than ever, when it runs Its been sitting for 8 years, but had these symptoms back then, I thought it was bad gas... ruled that out and have merrily replaced parts not seemingly needed... Help, thanks .. I will upload a second video of when it decided to run normally... baffles me ... I tried to add this as a reply to my older topic, not sure why it did not work. Sorry if I am duplicating.

 

[markjpro]

this time it worked at WOT, then the symptoms come back. I pull the vent out to insure the tank breathes..thanks

 

[scout-j-m]

Good videos.

Do you have a clear fuel filter between the pump and carb? If not add one and run it with the cowl off to see if the filter stays full of fuel or if it becomes empty.

 

[markjpro]

thats a great idea, will do thanks

 

[fmt2bx]

If you have a quick fuel disconnect between the tank and motor, try to bypass it by running a direct line from tank. I had similar issues, pump was good but the fuel disconnect was faulty.
good luck.

 

[markjpro]

yes, I took out the quick disconnect too.. I know I have improved the fuel delivery but the problem persists. So, I am gambling on a new power pack and then the whole CDI is upgraded. Then when I trailer out to the water I can have that upgrade and watch the fuel in the filter I installed as it throttles up with the cowling off. Thanks

 

[fmt2bx]

yes, I took out the quick disconnect too.. I know I have improved the fuel delivery but the problem persists. So, I am gambling on a new power pack and then the whole CDI is upgraded. Then when I trailer out to the water I can have that upgrade and watch the fuel in the filter I installed as it throttles up with the cowling off. Thanks

Once you install a clear filter between pump and carb you'll be able to tell if fuel is flowing properly.
When the engines quits, is it difficult to restart? Do you have to Prime?
Keep the primer in vertical position with arrow pointing up (sometimes the check valve gets sticky).
Try to run the motor with engine cowling off. See if problem persists.

Once you have eliminated a fuel issue, then you can start troubleshooting the electronic system. Of course it doesn't hurt to upgrade the electronics anyway.

All of the above I got from the vets here on this forum. It is time consuming but it is great advise. They really know what they are talking about.

cheers

 

[djsforce]

I watched your videos and it reminded me of a similar problem I had with my Force 50. A mechanic found one of the spark plug boots has a small crack in the rubber. I was pleasantly surprised that he found it, and mine has never cut out at high speed again after I replaced the spark plug wire. Mine was slightly different from what you are experiencing in that your problem is very consistent, mine was more sporatic and if I throttled back I could sometimes prevent it from stalling. Like yours, mine was running and idling well, and it only cut out at high speed. An easy thing to check anyway. Good luck!

 

[markjpro]

So, I replaced the power pack, now CDI, stator, power pack and trigger replaced, and all the work listed above. I put an inline clear filter and video ed the air bubbles, this is the third fuel pump, new lines, different tank tried (external 3 gal.), 2 fuel pumps, new diaphragm... the symptoms have never changed too much. One thing, the motor cuts a bit when I turn and the boat tilts... I suppose the float is not high enough. I have another carb for this motor that is probably fine, but what about those air bubbles? (see video) That's Blue Lake btw off CouerDAlene River.

Question. Whats is that hose from the bottom of the powerhead to above the carb ? It seems one way and transports gas/vapor from the bottom of the motor back into the intake. The hose is somewhat deteriorated but not blocked. I shot some gas through the fitting above the carb and and I think the symptoms changed. The push of air from both hoses to the fuel pump seem clear.

This motor gets me home but the symptoms persist. All and any help appreciated!

 

[Jiggz]

There is absolutely a fuel delivery problem as indicated by the clear fuel filter emptying. The bubbles indicate the fuel pump is working properly but it is sucking air, either from a torn or holed diaphragm or from a leaky fuel line upstream of the fuel pump (check the quick disconnect and also the primer bulb connections. This should be a quick fix considering you have basically localized the source of the problem. If there is a water separator in the fuel lines check make sure it is properly oriented with its connection. Or even better by-pass it for now while troubleshooting.

For the quick disconnect, for troubleshooting purposes, just wrap it up with a pipe wrap or even fuel resistant plastic and a wide rubber band. Test again to see if the clear fuel stays at least 1/2 full. if not, then wrap the connections on the primer bulb. Test again. And continue to wrap all fuel line connections as applicable. If problem persists, then open and inspect the fuel pump diaphragm for tears or holes.

 

[markjpro]

thank you Jiggz. I will replace fuel lines and clamps upstream and water test. I am leaving the quick disconnect off for now. I will bring the spare 3 gal. tank again to rule out the pickup tube, which is welded onto the built in tank. I tried the external tank once before and still had problems but I did not have the clear filter inline at the time. PNWBoat is helping me allot too. Thanks